This invention relates to an optical disk apparatus, and more particularly to a method and apparatus suitable for use in a tracking control system of the optical disk apparatus for aligning a beam spot with a desired track or leaading the beam spot in the desired track of an optical disk.
A prior art method of aligning a beam spot with a track of an optical disk loaded in an optical disk apparatus is disclosed in, for example, JP-A-51-107015. The method disclosed in JP-A-51-107015, comprises measuring and storing an eccentricity of a track, and forcedly deflecting the beam spot according to the stored data while reading out the stored data so that the beam spot can be shifted substantially in parallel to the track, thereby ensuring alignment of the beam spot with the track. However, the proposed method has been defective in that a relatively long period of time is required for storing the data of the eccentricity of the track. The proposed method has further been defective in that the beam-track aligning operation tends to become unstable when there occurs a beam-track misalignment resulting from a cause other than the eccentricity, for example, a track offset due to residual vibration of an optical head after a seek operation or due to an externally applied impact.